QA Testing (Playwright)

High-signal, cost-aware E2E testing for web applications.

Core docs:

• https://playwright.dev/docs/best-practices
• https://playwright.dev/docs/locators
• https://playwright.dev/docs/test-retries
• https://playwright.dev/docs/trace-viewer
• https://playwright.dev/docs/test-sharding
• https://playwright.dev/docs/ci

Defaults (2026)

• Keep E2E thin: protect critical user journeys only; push coverage down (unit/integration/contract).
• Locator priority: getByRole → getByLabel/getByText → getByTestId (fallback).
• Waiting: rely on Playwright auto-wait + web-first assertions; no sleeps/time-based waits.
• Isolation: tests must run alone, in parallel, and in any order; eliminate shared mutable state.
• Flake posture: retries are a debugging tool; treat rerun-pass as a failure signal and fix root cause.
• CI posture: smoke gate on PRs; shard/parallelize regression on schedule; always keep artifacts (trace/video/screenshot).

Quick Start

When to Use

• E2E tests for web applications
• Test user authentication flows
• Verify form submissions
• Test responsive designs
• Automate browser interactions
• Set up Playwright in CI/CD

When NOT to Use

Authoring Rules

Locator Strategy

// 1. Role locators (preferred)
await page.getByRole('button', { name: 'Sign in' }).click();

// 2. Label/text locators
await page.getByLabel('Email').fill('user@example.com');

// 3. Test IDs (fallback)
await page.getByTestId('user-avatar').click();

Flake Control

• Avoid sleeps; use Playwright auto-wait
• Use retries as signal, not a crutch
• Capture trace/screenshot/video on failure
• Prefer user-like interactions; avoid force: true

Workflow

• Write the smallest test that proves the user outcome (intent + oracle).
• Stabilize locators and assertions before adding more steps.
• Make state explicit: seed per test/worker, clean up deterministically, mock third-party boundaries.
• In CI: shard/parallelize, capture artifacts, and fail fast on rerun-pass flakes.

Debugging Checklist

If something is flaky:

• Open trace first; identify whether it is selector ambiguity, missing wait, or state leakage.
• Replace brittle selectors with semantic locators; replace sleeps with expect(...) or a targeted wait.
• Reduce global timeouts; add scoped timeouts only when the product truly needs it.
• If it only fails in CI, look for concurrency, cold-start, CPU starvation, and environment differences.

Do / Avoid

• Make tests independent and deterministic

• Use network mocking for third-party deps

• Run smoke E2E on PRs; full regression on schedule

• “Test everything E2E” as default

• Weakening assertions to “fix” flakes

• Auto-healing that weakens assertions

Resources

Templates

Related Skills